2026 American Academy of Neurology Abstract Website

Objective:

To investigate the utility of computed tomography (CT) head in distinguishing between tumefactive demyelinating lesions (TDL) and glioblastoma, IDH-wildtype (GBM).

Background:

TDL is challenging to diagnose, often mimicking high-grade glioma and potentially leading to unnecessary invasive procedures and delayed treatment. As patients typically present acutely, CT head is commonly obtained in the emergent setting, offering complementary diagnostic information to brain MRI.

Design/Methods:

This was a single center retrospective cross-sectional study of patients with TDL and GBM, with both MRI and CT head available within one week of each other. MRI included T1, T2/FLAIR, DWI, SWI and T1 enhanced sequences. The primary outcome was lesion attenuation pattern on CT head. Secondary outcomes included MRI enhancement characteristics, lesion number, and anatomical distribution. An expert neuroradiologist, blinded to the final diagnosis, performed the MRI and CT analysis.

Results:

A total of 77 patients were included: 39 TDL and 38 GBM.

TDL lesions were more likely to be isodense or hypodense on CT compared with normal brain than GBM (35/39, 90% vs. 9/38, 24%, p<0.001). TDL patients were more likely to have multiple enhancing lesions on post-gadolinium T1 sequences than GBM patients (19/39, 49% vs 10/38, 26% p=0.025). TDL lesions were more likely to be located in the frontal lobe (22/39, 56% vs 10/38, 26%, p=0.007).

Conclusions:

CT imaging provides a valuable, low-cost diagnostic tool for differentiating TDL from GBM, with isodense or hypodense lesions on CT head being more frequent with patients with TDL.